| Radiotherapy plays an important role in the treatment of malignant tumors. About 70 percent tumor patients would receive radiotherapy in the progress of disease. The average cure rate is only 50 percent when adopting the bearable dosage of normal tissue。 Ovarian cancer and cervical cancer are the most common malignant gynecological tumors, seriously threatening women' lives. Owing to high frequency of abdominal cavity metastasis and the existence of side complications, the life span, quality and survival of patients have been affected directly, while the radioresistance of these diseases has a bad effect on the radiotherapy. So how to increase the radiosensitivity has attracted significant interest to radiobiological research in recent years. Part OneObjective: To explore the effect and the mechanism of lipofectin-c-erbB2 or c-raf-1 antisense oligodeoxynucleotides on radiosensitivity in human ovarian cancer cell line SKOV3. Methods: There were four groups in the study: normal control group, Lipofectin control group, c-erbB-2 SODN (sense oligodeoxynucleotides) or c-raf-1 SODN experimental group, c-erbB-2 ASODN (antisense oligodeoxynucleotides) or c-raf-1 ASODN experimental group. The expression of c-erbB2 or c-raf-1 was detected by means of RT-PCR; cellular response to irradiation was evaluated by the colony forming test and MTT assay; Apoptosis and cell cycle were observed by flow cytometry, electronic microscope, fluorescent microscope. Results: Lipofectin- c-erbB2 or c-raf-1 ASODN could suppress the expression of c-erbB2 or c-raf-1, leading to different cell cycle arrests. They significantly decreased the proliferation rate and statistically increased the apoptosis rate of human ovarian cancer cells after ionizing irradiation (vs control group, p<0.01), while non-treament and the SODNs groups did not decrease the radio-resistance level of SKOV3 cell line (vs control group, p>0.05). Conclusions: c-erbB2 or c-raf-1 antisense oligodeoxynucleotides sensitized the SKOV3 to ionizing irradiation through decreasing the expression of c-erbB2 or c-raf-1, which might be the result of the fact that antisense oligodeoxynucleotides inhibit the celluar signal transduction pathway relating to the radiation-resistant phenotype, but there was no clear relationship between cell cycle distribution led by c-erbB2 or c-raf-1ASODNs and the radiosensitivity. Part TwoObjective: It was reported that the expressions of Ki-67 and Bcl-2 protein are associated with the resistance of radiotherapy, that is to say, the higher overexpression of Ki-67 or Bcl-2, the more resistant tumor cells might be. In the second part of the study, we investigated the effect of c-erbB-2 or c-raf-1 antisense oligodeoxynucleotides on expression of Ki-67,Bcl-2 protein in irradiated human ovarian cancer cell line SKOV3. Methods: Immunohistochemical method was performed to analysis expression of Ki-67, Bcl-2 protein in pre-or post-irradiated human ovarian cancer cells. There were four groups in the study, normal control group, Lipofectin control group, c-erbB-2 or c-raf-1 SODN experimental group, c-erbB-2 or c-raf-1 ASODN experimental group. Results: In terms of the c-erbB-2 post-irradiation experimental groups, the positive rate of Ki-67 were 42.7% in SODN group (VS control group p>0.05) and 19.8% in ASODN group (VS control group, p<0.01). Among c-raf-1 post-irradiation experimental groups, positive rates were 43.9% in SODN group (VS control group, p>0.05) and 19.8% in ASODN group(VS control group, p>0.05), while among c-erbB-2 experimental groups, positive rates of Bcl-2 were the 39.4% in SODN group (VS control group, p>0.05) and 20.7% in ASODN group(VS control group , p<0.01). Among c-raf-1 experimental groups, positive rates of Bcl-2 were 41.8% in SODN group(VS control group, p>0.05) and 21.7% in ASODN group(VS control group , p>0.05) respectively. Results: c-erbB-2 ASODN or c-raf-1 ASODN significantly inhibited the expression of Ki-67 and Bcl-2 protein in human ovarian cancer cells after ionizing...
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